<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <span class="s">hello world</span>

    <script src="./jq.js"></script>
    <script>
        const span = q('.s');
        // span.

        // DOM & BOM 之后写法用的少

        // span.addEventListener('click', function () {});
        // span.on('click', function () {})

    </script>
</body>
</html>